This disposable and breakaway nozzle connector relates in general to means for preventing and stopping fluid passage through a flow line, such as a gasoline line used in conjunction with fuel dispensing at a service station, and more specifically to improvements within the connector useful when a severance occurs in the line, and when a loss of fluid may be encountered, such as when a vehicle may drive off with the gasoline nozzle inadvertently still inserted within the vehicle fuel tank. A unique aspect of the present connector is a trio of O-rings that reduce pressure on the shear pins, and thus reducing premature breaks in the connector. This invention is especially useful when applied in a fuel line, and functions as a check valve to prevent fuel flow under particular adverse conditions, particularly when the breakaway hose is disconnected.
As is well known in the art and the public, fuel dispensing nozzles as used in most service stations have a spout which is inserted into the inlet of the filler pipe of a vehicle fuel tank. The diameter of the spout is less than that of the filler pipe and consequently, fuel vapors escaped into the atmosphere. Escaped fuel vapors raised pollution concerns and triggered government regulation of fuel dispensing nozzles. Environmental requirements have made it essential that vapors and fumes generated during fuel dispensing be collected to prevent the emission of such fumes into the atmosphere. Environmentalists have stated that these types of fumes may be detrimental to the quality of our air.
Numerous valves in the prior art furnish a shut-off of fluid or other fuel flow, and more particularly, such mechanisms normally are utilized in lines where fuel may be flowing, and generally in those situations when the conduit comprises the fuel line leading from a fuel dispenser to its nozzle. For example, as can be seen in the U.S. Pat. No. 2,642,297, to Hanna, a breakaway coupling responds to tension in the line and is held together through a combination of male and female couplings, and detents that provide bearing engagement between the two components. In addition, the U.S. Pat. Nos. 4,617,975, and 4,691,941, to Rabushka, disclose various types of tension actuated uncouplers, for delivering gasoline to a vehicle from a gas pump. These prior patents portray devices that tend to leak, and when any internal pressure is exerted within the fuel line, such as may occur when pumping the fuel, excessive pressures may momentarily arise within the fuel line, and particularly at the location of the uncoupler, and in some instances, has actually forced the coupling device to prematurely come apart. Obviously, this is not desirable or acceptable.
This predicament has generally been recognized by the Applicant as primarily occurring in those breakaway couplings that are constructed having unequal internal surfaces. The internal surfaces cause greater fluid forces to be exerted in one direction upon one part of the breakaway coupling than is exerted upon the other, and are inherent because of the construction of the breakaway coupling device. When these spontaneous and unequal high pressures are encountered, the pressure exerted upon one component of the breakaway coupling device in one direction, is substantially different from the fluid pressure that may be exerted upon the other component of the breakaway coupling device, and therefore, this pressure disparity tends to force the coupler to prematurely separate, in an untimely and dangerous fashion. This can and has occurred particularly where the fluid pressure in the hose may undertake a phenomenon that is equivalent to “water hammer.”
Originally from water supply plumbing, water hammer refers to the concussion induced into plumbing by water brought to a sudden stop. In an evacuated hose, fitting, or nozzle, fuel in the absence of air can cause a similar concussion to a fuel line or coupling as a moving mass of fuel suddenly stops. Couplings endure this concussion generally as fueling stops when a nozzle automatically or manually shuts off, often abruptly.
The lengths of hose, fittings, and nozzles require connection among themselves and to service station pumping facilities. Hoses, fittings, and nozzles have couplings that breakaway when an errant motorist drives away with a hose in a vehicle, and thus preventing a fiery catastrophe. Until a breakaway, a coupling joins two sections of a fueling line and permits passage of fuel therethrough. As fuel pumps through the flow line, pressure spikes over rather significantly and substantially throughout the hose, momentarily, and even at the location of the coupling, as when the flow is suddenly stopped, as for example, when the fuel tank is full. Hence, leakage at such couplers has frequently occurred in the field, and on occasion, as previously explained, untimely separation of the coupling has happened.
Couplings generally have two halves, a male fitting and a female fitting the male fitting joins to a hose, fitting or nozzle and has an extended spacer means. The female fitting joins to a second hose, fitting, or nozzle and has a hollow cylindrical center to receive a spacer means. The female fitting engages the coupling by two diametrically opposed shear pins provided towards the rear of the female fitting and a plurality of locking bearings towards the front of the female fitting. Upon inserting the spacer means into the female fitting, the male fitting abuts the locking bearings.
Between the locking bearings and the shear pins, pressure rises and falls depending upon the fuel flow through the coupling and the male fitting and the female fitting. Prior art designs provided an empty space between the locking bearings and the shear pins to absorb pressure fluctuations. In use though, the “water hammer” like effects during fueling induced excessive pressure upon the shear pins which would break repeatedly even with proper fueling and nozzle handling by motorists. Such nuisance breaks occur often and service stations then have to close a pump temporarily while the existing coupling is replaced.